Cable reel of electric signal transmission apparatus

Abstract: A cable reel of an electric signal transmission apparatus includes a tape-shaped cable for absorbing a relative rotation by tighting and loosening of winding of said tape-shaped cable, a housing including an inner cylinder having a flange portion and outer cylinder having side and bottom surface portions, wherein an upper portion of said side surface portion is engaged with and covered by said flange portion of said inner cylinder.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable reel of an electric signal transmission apparatus for an electrical connection between a stationary port and a movable port employing a tape-shaped cable, and particularly to a cable reel suitable for use in a steering device of a vehicle. 2. Description of the Related Art In the case where signal transmission is performed between the handle side of a car and the car body side thereof, such a device as shown in Fig. 2 is used. That is, a tape-shaped cable is spirally accommodated in a housing having an inner cylinder and an outer cylinder so that the rotation of a handle is absorbed by tightening and loosening of the winding of the tape-shaped cable. Such a cable reel is disclosed in US-A-4 975 063. As shown in Fig. 2, a conventional cable reel includes a housing having an inner cylinder 1, outer cylinder 2 and holder 12, and a tape-shaped cable 5 which is spirally wound and housed in the housing. The inner top end portion of the tape-shaped cable 5 is pulled out from the housing through a hole 10 of the inner cylinder 1 to the outside of the housing. Then, the tape-shaped cable is assembled to the inner cylinder 1, and the outer top end portion of the tape-shaped cable 5 is pulled out from the housing through a hole 11 of the outer cylinder 2 so that a grasping portion 9 is pulled out from the housing through the hole 11. After the grasping portion 9 is supported around the hole 11, the inner cylinder 1 and outer cylinder 2 are rotatably connected to each other. Further, connectors are fixed to both end portions of the tape-shaped cable 5 being pulled out from the housing so that the inner and outer end portions sides are connected to a control unit and an inflator side, respectively. Accordingly, the tape-shaped cable 5 in the housing makes the electrical connection between the control unit and the inflator be possible. In the apparatus of Fig. 2, there has been a problem in that the structure of the outer cylinder 2 is so complicated that it is difficult to form the outer cylinder 2 through injection molding and the metal mold is quite complicated and expensive. Further, in assembling the cable reel, it is necessary that a tape-shaped cable be passed through holes 10 and 11 formed through the inner and outer cylinder respectively, and that respective end grasping portions 8 and 9 provided on the tape-shaped cable 5 in advance are fixed on the inner and outer cylinders by using a lock mechanism. The work for passing a tape-shaped cable 5 through the respective holes 10 and 11 of the inner and outer cylinders 1 and 2 as described above is troublesome, and the assembly cannot be automatized as long as such work is required. SUMMARY OF THE INVENTION In order to solve the above problems, it is an object of the present invention to provide a cable reel for an electric signal transmission in which the efficiency of assembling can be improved and the assembling work can be automatized. This object is solved with a cable reel according to claim 1. A preferred embodiment is shown in claim 2. BRIEF DESCRIPTION OF THE DRAWINGS In the accompany drawings, Fig. 1 is a diagram showing a state of the cable reel according to the present invention before assembly; Fig. 2 is a diagram showing a state of the conventional cable reel before assembly; and Fig. 3 is a perspective view of an example of a tape-shaped cable used in an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to Fig. 1. An outer cylinder 2 is divided into side and end surface portions 2A and 2B. The side surface portion 2A has a guide portion 4 projecting therefrom for drawing a tape-shaped cable out. The end surface portion 2B ("bottom" portion in the view of Fig. 1) has an end projecting portion 15 for supporting a beginning grasping member 7 when fitted to the guide portion 4, and a circular opening portion 17 into which a cylindrical portion 16 of an inner cylinder 1 is inserted. The inner cylinder 1 has a notch portion 3, a flange portion 14 on an end surface portion 25 and the cylindrical portion 16. A beginning and an end portion of the tape-shaped cable 5 are provided with a beginning and an end grasping member 7 and 6, respectively, to which molded parts are fitted so as to hold the tape-shaped cable. Further, the beginning and the end grasping member 7 and 6 fit to the guide portion 4 and notch portion 3, respectively. The inner cylinder 1 having the notch portion 3 to which the end grasping member 6 fit is inserted and fit to the inside of the side surface portion 2A so that an upper portion of the side surface portion 2A is engaged with the flange portion 14 on the end portion of the inner cylinder 1, and further, the upper portion of the side surface portion 2A is covered by the end surface 25. The cylindrical portion 16 of the inner cylinder 1 fitting into the side surface portion 2A is inserted into the circular opening 17 of the end surface potion 2B, and a holder 13 having a flange portion is inserted into the cylindrical portion 16 from the bottom, except for the flange portion of the holder, for fixing each other. A preferable tape-shaped cable 3 used in this embodiment includes a plurality of conductors 21 and insulated members 22 for holding the conductors therebetween. For example, as shown in Fig. 3, two insulated members 22 having a thickness of about 100 µm are laminated to each other to hold three conductors 21 made of tin plated hard copper having a thickness of 0.15 mm and a width of 1.5 mm therebetween. According to the structure of the cable reel as shown in Fig. 1, it is possible to easily perform injection molding and to simplify the metal mold. Further, assembly can be performed from one direction to thereby improve the efficiency in the assembly work as well as the reliability in the assembly. In addition, the assembly time of the cable reel in the present invention can be reduced to 30-50% of that of the conventional cable reel assembly.

Claims: A cable reel for an electric signal transmission apparatus comprising: a tape-shaped cable (5) beginning (7) and end (6) grasping members which are provided at beginning and end portions of said tape-shaped cable (5), respectively; an inner cylinder (1) including a cylindrical portion (16), a first end surface portion (25), a first flange portion (14) with a notch portion (3) into which said end grasping member (6) is fitted; an outer cylinder (2) including a second end surface portion (2B) opposing said first end surface portion (25) and having a circular opening (17) into which said cylindrical portion (16) of said inner cylinder (1) is inserted and fixed, and a side surface portion (2A) having a guide portion (4) onto which said beginning grasping member (7) is fitted; wherein said tape-shaped cable is spirally wound for allowing absorbing a relative rotation between said inner and outer cylinders by tightening or loosening of windings of said tape-shaped cable; and a holding member (13) having a second flange portion, which holding member is inserted into said cylindrical portion (16) of said inner cylinder (1) for fixing them to each other; wherein a portion of said side surface portion (2A) distant from said second end surface portion (2B) is engaged with and covered by said first flange portion (14) of said inner cylinder (1). A cable reel according to claim 1, wherein each of said beginning (7) and end (6) grasping members is formed by molded parts which are fitted so as to hold said tape-shaped cable.

Inventors: KIHARA TAKESHI, SAEN HARUO, SAKAMOTO YOSHITO, KIHARA, TAKESHI, SAEN, HARUO, SAKAMOTO, YOSHITO, KIHARA, TAKESHI, C/O KANTOH WORKS OF, SAEN, HARUO, C/O KANTOH WORKS OF, SAKAMOTO, YOSHITO, C/O KANTOH WORKS OF
Applicants: SUMITOMO ELECTRIC INDUSTRIES, SUMITOMO ELECTRIC INDUSTRIES, LTD.
Application year: 1994
Main classification: H01R35
IPC codes: B60R16, H02G11, B62D1, H01R35